The present invention relates to a mounting device for mounting an image forming apparatus such as an electrographic color copying machine or a color printer.
The mounting device of this type has a paper feed function, so that a plurality of types of paper sheets can be fed into an image forming apparatus (hereinafter the mounting device will be referred to as a "paper feed rack"). In some of the paper feed racks, a paper feed speed can be changed in accordance with a copying speed of the image forming apparatus, that is, a paper transfer speed.
Methods for changing the paper transfer speed include a method of exchanging a drive gear with a gear having a different number of teeth or a method of controlling a rotation number of a drive motor. Furthermore, a method is known using two electro-magnetic clutches different in the number of teeth. In this method, one of the two electromagnetic clutches is regularly connected and the other is connected at occasions when the speed is required to be changed.
However, in the method of exchanging the drive gear, a service technician has to disassemble the machine more or less. Therefore, time and labor are required.
In the method of controlling the rotation number of the drive motor, if the paper transfer speed is changed from e.g., 260 mm/sec to 400 mm/sec, the rotation number of the drive motor results in 1.5 times. It is therefore extremely difficult to change the paper transfer speed by the method using the drive motor.
Furthermore, in the method of using the electro-magnetic clutches, one of the electromagnetic clutches is always left unused, with the result that the cost increases.